There are some practical quirks to the realities of chess tournaments, and who wants to play who, which I bet lead to a lot of deviation. In practice, a super

There are some practical quirks to the realities of chess tournaments, and who wants to play who, which I bet lead to a lot of deviation. In practice, a super GM in their late 30s would hate to be playing up and coming teenagers that just made GM since they are underrated (Those kids gain 200+ points of ELO in a year or two) and the older GM is probably getting worse anyway. So, in practice, there is a difficult transition to get a high enough ELO vs regular GMs and IMs to have good chances to aim for a 2700, where the real gains are at. Add to that the fact that there are few classical tournaments, while the youth is training in blitz online, and you can find pretty deceptive ELOs out there.